Arctic melt bottoms out at new record low

This year's melt (blue) has ended up well below 2007's record (green).

NSIDC

Yesterday, the National Snow and Ice Data Center announced that the Arctic melt season was probably over. This year's melt had already set records back in August, so the only real question was just how low it would go. Assuming there's not a downward fluctuation during the next couple of weeks, the answer is 3.41 million square kilometers, or about half of the typical low point observed from 1980-2000. That's about 750,000 square kilometers below the previous low (set in 2007), an area roughly equivalent to that occupied by Texas.

In fact, as the NSIDC notes, every year since 2007 has seen unusually strong summer melts: "The six lowest seasonal minimum ice extents in the satellite record have all occurred in the last six years." Although weather has undoubtably played a role in making this year's melt unusually severe, the strong tendency toward record amounts of open water in the Arctic Ocean seems to lend credence to the ideas of Cornell professor Charles H. Greene, who has referred to recent trends as signs that we've entered what he called an "Arctic warm period."

One of the surprising aspects of all of this is that it's happening much faster than most climate models have predicted. Many of them had been indicating the ice would be relatively stable for most of the current century.

This is even more surprising considering that the models appear to get the Antarctic, where sea ice is expanding, largely right. A 2010 study used climate models to track the impact of warming waters in the Southern Ocean. It found that the warming produced increased snow, which contributed to keeping existing ice cold and added to the glaciers that feed floating ice sheets. It also created a layer of fresh water that stays on the surface, insulating the ice from warmer ocean waters below. The result is an ice sheet that is growing despite the warming climate. These models do suggest that a turning point is likely to be reached by mid-century under most emissions scenarios, as more of the moisture will start falling as rain.

It may be tempting to dismiss these projections, given that the Arctic is melting so much faster than predicted. But the two poles have radically different behavior, at least in part due to the fact that one is an ocean that is largely surrounded by land, while the other is a continent surrounded by ocean. As a result, the models have to contend with very different things in each location, and they may handle some of these much better than others.

"One of the surprising aspects of all of this is that it's happening much faster than most climate models have predicted. Many of them had been indicating the ice would be relatively stable for most of the current century."

One could take this a couple ways - perhaps the models are not accurate and are missing some knock-on effects of global warming.

On the other hand - perhaps the models are accurate to the effects of global warming, and the observed melting is not being caused by global warming, but by some other mechanism.

Further, taking a look at the temperature anomoly for the northern hemisphere for the last decade, a period of time where the summer ice has shrunk dramatically, you don't see a dramatic increase in the anomaly, in fact 2007 was hotter than 2012 (at least so far).

You know how a glass of ice water is more or less the same temperature? The ice being just a little below 0º and the water staying just a little above 0º. And the system seems pretty stable around 0º until all the ice is gone, and only then can the water finally start warming up.

I always wonder how quickly the planet's water will warm up once the ice cubes are done melting.

We went to 24% coverage of sea ice this yea and I didn't notice anything bad except some drought in the midwest thru texas. I now no longer care about global warming, I want to see no ice coverage in the arctic ocean. This could lead to new faster shipping routes and open up new areas to mining.

The 1979-2000 line in the graph also shows a +/- 2 standard deviation. What's to say that 2012 isn't just a -2 standard deviation from 2007? Or am I looking at this in the completely wrong manner?

A standard deviation is measured from a mean. If you take 20 samples and build a nice normally distributed bell curve, you would expect 68% (~14) samples to be within 1 standard deviation. 95% of the samples (~19) should be within 2 standard deviations. 99.6% (all 20, most likely) should be within 3 standard deviations.

So far so good? Here's the issue: you can't take that one outlier that's probably between 2 and 3 standard deviations and go 2 standard deviations from *it*. That would effectively be between 4 and 5 standard deviations from the mean of the population. In a 20 sample set, it's pretty unlikely (but not impossible, of course).

Someone better at statistics than me can likely calculate the probability that one sample in a set of this size would fall that far from the mean. I'm pretty sure it will be a vanishingly small number (but I'd love to see the math).

We went to 24% coverage of sea ice this yea and I didn't notice anything bad except some drought in the midwest thru texas. I now no longer care about global warming, I want to see no ice coverage in the arctic ocean. This could lead to new faster shipping routes and open up new areas to mining.

We went to 24% coverage of sea ice this yea and I didn't notice anything bad except some drought in the midwest thru texas. I now no longer care about global warming, I want to see no ice coverage in the arctic ocean. This could lead to new faster shipping routes and open up new areas to mining.

As predicted by climate models? Here is 5 year old Nature article:http://www.nature.com/news/2007/070329/ ... 26-11.htmlScroll down to "John Mercer effect" who analyzed multiple models and predicted 5 m sea rise during next 50 years. I don't know if most scientists disagreed or criticized him -- the paper is cited 500 times, and you usually cite the paper you agree with.

It's because for the 60 years prior, the arctic kept getting thicker and thicker until, in the mid 70s, environmentalists-crazies were sounding the alarm and Time magazine wrote an article in 1974 entitled "Another Ice Age" - http://www.freerepublic.com/focus/f-news/1663607/posts.

Just to give you a small taste:

"Since the 1940s the mean global temperature has dropped about 2.7° F....Man, too, may be somewhat responsible for the cooling trend. The University of Wisconsin's Reid A. Bryson and other climatologists suggest that dust and other particles released into the atmosphere as a result of farming and fuel burning may be blocking more and more sunlight from reaching and heating the surface of the earth....Whatever the cause of the cooling trend, its effects could be extremely serious, if not catastrophic."

It just goes to show how easy it is to lie with charts/data.

I'm not say there is or isn't global warming. I'm saying the chart at the top of page is misleading and whoever made it deliberately left out the previous 30 years IN ORDER to mislead you.

It's because for the 60 years prior, the arctic kept getting thicker and thicker until, in the mid 70s, environmentalists-crazies were sounding the alarm and Time magazine wrote an article in 1974 entitled "Another Ice Age" - http://www.freerepublic.com/focus/f-news/1663607/posts.

Just to give you a small taste:

"Since the 1940s the mean global temperature has dropped about 2.7° F....Man, too, may be somewhat responsible for the cooling trend. The University of Wisconsin's Reid A. Bryson and other climatologists suggest that dust and other particles released into the atmosphere as a result of farming and fuel burning may be blocking more and more sunlight from reaching and heating the surface of the earth....Whatever the cause of the cooling trend, its effects could be extremely serious, if not catastrophic."

It just goes to show how easy it is to lie with charts/data.

I'm not say there is or isn't global warming. I'm saying the chart at the top of page is misleading and whoever made it deliberately left out the previous 30 years IN ORDER to mislead you.

I think you're confused. If they had included the data sets of the ice-growing-years, that average curve (currently at 1979-2000) would look even FARTHER away from the current 2012 curve, making it seem like an even bigger problem.

If the ice was getting THICKER from 1940-1979 (which it was), and 1979 is the thickest it has been in 100 years, then the trendlines/averages over a longer range would be lower and 2012 would be closer to or within the norm.

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In terms of the satellite imagery, you are correct that the thickness was measured with much greater accuracy starting in the late 1970s with the introduction of satellite measurements, but sea ice thickness measurements go back to the 1800s and, even if they aren't as precise as the satellite measurements, they are still informative.

It always surprises me that people who are ostensibly rational on this subject find inconvenient information to be trolling. Nothing I said was objectionable or inaccurate. Everything is backed up by measurements taken by people with no agenda. Don't be afraid of information.

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As an aside, I am neither a global-warming zealot nor a "Its all a conspiracy" nutjob. I've just been around long enough to know that the level of confidence in these issues is not backed up by the evidence and when evidence IS presented, it is often slanted in a specific way to serve an agenda. The chart at the top of this page is a prime example.

As predicted by climate models? Here is 5 year old Nature article:http://www.nature.com/news/2007/070329/ ... 26-11.htmlScroll down to "John Mercer effect" who analyzed multiple models and predicted 5 m sea rise during next 50 years. I don't know if most scientists disagreed or criticized him -- the paper is cited 500 times, and you usually cite the paper you agree with.

Actually, no. You also cite papers when you demonstrate they did something wrong.

If the ice was getting THICKER from 1940-1979 (which it was), and 1979 is the thickest it has been in 100 years, then the trendlines/averages over a longer range would be lower and 2012 would be closer to or within the norm.

---

In terms of the satellite imagery, you are correct that the thickness was measured with much greater accuracy starting in the late 1970s with the introduction of satellite measurements, but sea ice thickness measurements go back to the 1800s and, even if they aren't as precise as the satellite measurements, they are still informative.

It always surprises me that people who are ostensibly rational on this subject find inconvenient information to be trolling. Nothing I said was objectionable or inaccurate. Everything is backed up by measurements taken by people with no agenda. Don't be afraid of information.

--

As an aside, I am neither a global-warming zealot nor a "Its all a conspiracy" nutjob. I've just been around long enough to know that the level of confidence in these issues is not backed up by the evidence and when evidence IS presented, it is often slanted in a specific way to serve an agenda. The chart at the top of this page is a prime example.

You are confused these measurements are based off of satellite data. These satellites that measure the polar ice caps have only been in orbit since 1979.http://arctic.atmos.uiuc.edu/cryosphere/archive.htmlI have included a link to an archive that contains a picture of the data.It is the data that we used today. This data it is more reliably complete data than what was available before and anything before 1950 is really really questionable.

We went to 24% coverage of sea ice this yea and I didn't notice anything bad except some drought in the midwest thru texas. I now no longer care about global warming, I want to see no ice coverage in the arctic ocean. This could lead to new faster shipping routes and open up new areas to mining.

The cons of global warming has been over blown in my opinion.

So you're not worried that the price of grain has gone up 35-40% (as a result of the crop failures) in the last 4 months?

You should be... at the very least the complete loss of Arctic ice will make a steak too expensive for you to afford. Animals raised for food consume around 7x their own bodyweight in foodstuffs, so any change in the cost of grain will be multiplied in the cost of meat.

Of course the worst case scenario is that we'll all be fighting each other for what little food there is.

This year is only a tiny inkling of the weather & crop disruption that will almost certainly happen when the ice cap finally does melt.

"Global Warming" is a marketing ploy to instill panic in the masses. (aside from the fact that the planet is warming)

So, you're convinced that digging up and burning all the carbon that has been naturally captured (in the form of dead plants and animals) over the last 300 million years (or so) won't return the temperatures back to those experienced 300 million years ago?

Wait a minute, an explanation for increased ice cover in antarctic is more snowing? Then, wouldn't increased temperature in arctic cause the same effect? Not to mention that ice formation through snowing seems highly dubious proposal -- wouldn't it be more likely for ice particles just grow by freezing neighboring subzero temperature water layer? I find it is much more probable that the ice cover is perfect proxy for water temperature, and their southern ocean temperature record is faulty. Why can't those "researchers" just admit that they have no clue what is going on in antarctic.

If the ice was getting THICKER from 1940-1979 (which it was), and 1979 is the thickest it has been in 100 years, then the trendlines/averages over a longer range would be lower and 2012 would be closer to or within the norm.

---

In terms of the satellite imagery, you are correct that the thickness was measured with much greater accuracy starting in the late 1970s with the introduction of satellite measurements, but sea ice thickness measurements go back to the 1800s and, even if they aren't as precise as the satellite measurements, they are still informative.

It always surprises me that people who are ostensibly rational on this subject find inconvenient information to be trolling. Nothing I said was objectionable or inaccurate. Everything is backed up by measurements taken by people with no agenda. Don't be afraid of information.

--

As an aside, I am neither a global-warming zealot nor a "Its all a conspiracy" nutjob. I've just been around long enough to know that the level of confidence in these issues is not backed up by the evidence and when evidence IS presented, it is often slanted in a specific way to serve an agenda. The chart at the top of this page is a prime example.

Wait a minute, an explanation for increased ice cover in antarctic is more snowing? Then, wouldn't increased temperature in arctic cause the same effect? Not to mention that ice formation through snowing seems highly dubious proposal -- wouldn't it be more likely for ice particles just grow by freezing neighboring subzero temperature water layer? I find it is much more probable that the ice cover is perfect proxy for water temperature, and their southern ocean temperature record is faulty. Why can't those "researchers" just admit that they have no clue what is going on in antarctic.

The key difference between the antarctic ice cap and the arctic ice cap is that one is primarily over land, and the other is entirely over water. Warmer ocean water erodes the ice shelves around antarctica even as the antarctic ice over land thickens due to snowfall. With no land to protect the northern ice cap from warmer ocean waters, the ice simply melts.

It feels like we're on that pedal powered bar headed towards a cliff but whoever is steering is more concerned with how much money they're making and even though a few people can see the cliff and have taken their feet off the pedals, most people are still pedaling as hard as they can, while some are adamantly declaring there is no cliff up ahead at all.. Maybe it's not a cliff, just the crest to a hill with a steep, but not exactly deadly, gradient..

Anyway, my point is it doesn't look like we're stopping anytime soon, so somebody get me another beer.

Wait a minute, an explanation for increased ice cover in antarctic is more snowing? Then, wouldn't increased temperature in arctic cause the same effect? Not to mention that ice formation through snowing seems highly dubious proposal -- wouldn't it be more likely for ice particles just grow by freezing neighboring subzero temperature water layer? I find it is much more probable that the ice cover is perfect proxy for water temperature, and their southern ocean temperature record is faulty. Why can't those "researchers" just admit that they have no clue what is going on in antarctic.

The key difference between the antarctic ice cap and the arctic ice cap is that one is primarily over land, and the other is entirely over water. Warmer ocean water erodes the ice shelves around antarctica even as the antarctic ice over land thickens due to snowfall. With no land to protect the northern ice cap from warmer ocean waters, the ice simply melts.

The 2010 article by J.Curry is about antarctic sea ice, not ice shelf. A little research evidences that sea ice formation due to increased snowfall is not entirely impossible: http://en.wikipedia.org/wiki/Sea_ice_growth_processes (snow deposition)However, there is long chain of "if"s and "might be"s before that explanation becomes convincing.

You've gotta be kidding. So now melting ice proves warming and increasing ice also proves warming. What passes for discussion on climate change is a joke. The models did not correctly predict incresing ice in the Antarctic. The models were spectacularly wrong in this respect. See this paper: http://journals.ametsoc.org/doi/abs/10. ... 12-00068.1.

If you can find any model that predicts increasing ice in Antarctica then it is certain that the model has been developed post the fact.